Spacer for a fire-rated air bar

ABSTRACT

An air bar has supports made of a low temperature melting point material located between the side rails. A high temperature melting point spacer assembly is frictionally fitted between the side rails of the air bar, at periodic points along the air bar, to support the side rails and prevent their collapse in a fire.

United States Paten Hartzell et a1.

Jan. 1974 SPACER FOR A FIRE-RATED AIR BAR Inventors: Lyndon G. Hartzell,Gaithersburg,

Md.; James C. Ollinger, Lancaster, Pa.

Armstrong Cork Company, Lancaster, Pa.

Fi led: May 1, 1972 Appl. No.: 249,039

Assignee:

U.S. Cl 98/40 D, 52/484, 287/189.36 D Int. Cl. F 24f 13/06 Field ofSearch 52/221, 484 X, DIG. 5; 287/189.36 D; 138/112, 113, 68 C; 98/40 D,40 C References Cited UNITED STATES PATENTS Lambert 98/40 D 360,7824/1887 3,002,443 10/ 1 961 3,343,250 9/1967 3,444,801 5/ 1969 Lambert98/40 D Primary Examiner-William E. Wayner Attorney-Clifford B. Price 57ABSTRACT An air bar has supports made of a low temperature melting pointmaterial located between the side rails.

A high temperature melting point spacer assembly is frictionally fittedbetween the side rails of the air bar, at periodic points along the airbar, to support the side rails and prevent their collapse in a fire.

5 Claims, 3 Drawing Figures SPACER FOR A FIRE-RATED AIR BAR BACKGROUNDOF THE INVENTION 1. Field of the Invention The invention relates to thefield of suspended ceiling system ventilating devices and, moreparticularly, to a fire-resistant air bar for use in a fire-resistantsuspended ceiling system.

2. Description of the Prior Art The rooms of buildings and otherstructures are provided with a decorative and aesthetically pleasingsuspended ceiling located below the real ceiling of the room. Suchsuspended ceilings usually include a framework of main runners and crossrunners on which are supported ceiling tiles to separate an attic spacefrom the room below. In this attic space, typically is located the airconditioning equipment I such as air plenum chambers, ducts, etc., forsupplying conditioned air to and for returning air from the room below.In order for the air to pass from the attic space to the room below, airbars are located in the framework of the suspended ceiling. 7

Typically, an air bar has a pair of side rails spaced apart by spacersand has air control means, such as nested weirs, located therebetween sothat air will controllably flow through an air bar to pass through thesuspended ceiling. The side rails of the air bar addition- 7 allysupport the adjacent ceiling tiles of the suspended ceiling to be anintegral part of the suspended ceiling framework.

In many of the buildings, the suspended ceilings are designed to be afire barricade. Such suspended ceilings have main runners and crossrunners made of a high melting point material and have fire-resistantceiling tiles. However, it is not easy to make the air bars of thesuspended ceiling system out of high melting point material because ofthe complicated shapes of some of the parts thereof. The side rails andthe nestedweirs have relatively simple shapes and so can be formed ofhigh melting point material. However, the spacers which separate boththe side rails and mount the nested weirs,

have complicated shapes; therefore, the spacers were typically extrudedinto their complicated shape. The

high melting point material cannot be readily and inexpensively extrudedin the complicated spacer shapes and so the spacers heretofore havebeen. extruded from lower melting point material.

If an air bar, having side rails and nestedweirs' made of high meltingpoint material, were assembled with extruded spacers made of a lowmelting point material, and were included in a fire-resistant ceiling,the effectiveness of the ceiling as a fire blockade would be reduced. Inthe case of a fire, the spacers would soften and possibly 'melt to dropthe nested weirs and to allow the side rails to pivot and drop thefire-resistant ceiling tiles, leaving a hole in the suspended ceilingthrough I which the fire could spread. What is'needed then is an air barwhich will maintainitsspacingeven through the standard two hourfire-rating test. In addition, the spacers are normally spaced arelatively large distance apart. Heat will cause buckling of the siderails in the region between two spacers and this can also result in thedropping of ceiling tiles from the suspended ceiling system.

Consequently, what is needed is a rather inexpensive system ofperiodically spacing apart the side rails of conventional air bars witha high melting point material so that conventional air bars can pass astandard two hour fire-rating test.

SUMMARY OF THE INVENTION The invention herein is a spacer retainer whichis inserted into an air bar for the purpose of securing a fire ratingfor the air bar. The spacer retainer is of a rectangular shape with awidth such that will allow it to pass through the bottom air slot of theair bar, and a length wbich is equal to the space between the side railsof the air bar. The spacer retainer is inserted lengthwise through theair slot, past the bottom flanges of the air bar, and then rotated Theair bar side rails have sufficient spring to allow this rotation. Africtional fit against the side rails and the presence of the bottomflanges of the air bar slot hold the spacer firmly in place. Normally anair bar is composed of two weir assemblies which have supports at eachend of the air bar and a support at the center of the air bar. Threespacer retainers are then used in each air bar; one by the center airweir support, and one in between the center air weir support and the endair weir supports at each end of the air bar.

The spacer retainer can be made of a number of materials and indifferent shapes. However, the major requirement for shape is one suchthat it may be readily inserted in place and it will space the siderails apart. Normally the appearance of the spacer retainer is notobjectionable since both the slot interior and the spacers are paintedblack and will normally not be noticeable by an observer from the roombelow the suspended ceiling system.

BRIEF DESCRIPTION OF THE DRAWING 'FIG. I is a cross-sectional side viewof an air bar;

FIG. II is a partially open side view of an air bar assembly; and

FIG. III is a perspective view of a typical spacer retainer structure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical air bar structure isshown in U. S. Pat. No. 3,411,425. The air bar has side rails withflanges 11 that define the air opening. Within the air bar, weirs- 440areused to control the flow of air through the air bar and the weirs-aresupported by a support structure FIGS. I and II ofthe drawing herein area showing of the commercially available system which is covered by theabove-mentioned patent. Herein, the air bar assembly 2 is composed oftwo side rails 4. An air inlet opening 6 is positioned at the top of theair bar and an air outlet opening 8 is defined by the two flangestructures 10. The side rails also have flange structures 12 on whichare supported ceiling tiles 1d. Air weir supports 16 are placed betweenthe two side rails 4 to space the side rails and to support the airweirs. A fire-resistant bar 18 is used in conjunction with the air weirsupport 16.

The air weir support structure can better be seen in the exposed area ofthe FIG. II drawing. The air weir support 16 is generally a channelshape structure on which the ends of the air weirs rest for support.Normally structure 16 is an extruded aluminum structure. During afire-rating test, the aluminum structure would tend to melt. This wouldthen eliminate the support for the side rails 4. The side rails 4 couldthen collapse towards each other and this would remove the flanges 12from their supporting function of the ceiling tiles 14. The ceilingtiles would then drop to the fioor providing an exposed area into whichthe fire could spread to the region beyond the suspended ceiling. Inorder to compensate for the low melting point material which is used inthe air weir supports 16, a reinforcing bar 18 has been providedadjacent the air weir support 16. This bar is usually a high temperaturemelting point material and would have tabs 24 on the end thereof, whichpass through the side rails and are bent along the side rails to holdthe bar 18 in position. This bar 18 wouldbe unaffected by a fire andwould therefore help to support the side rails in position during a firetest.

Normally the air weirs 20 are two or more feet in length. A supportstructure 24 would be provided at each end of the air bar and ahightemperature material bar 22 would be provided therein also.Consequently, in the normal air bar there would be provided two air weirstructures. Normally three supports would be provided; one at each endof the air bar, and one at the center of the air bar to support the twoair weirs in position within the air bar. As was indicated above, duringa normal fire test, the melting of the support 16 would sometimes fluxthe high temperature melting point material of bars 18 and 22 and causethem to actually melt during a standard two hour fire test. In addition,the

' structure which may be utilized to help the air bar of FIGS. I and IIpass a standard two hour fire test. A typical spacer retainer 26 isshown in FIG. III. This spacer retainer is shown in position in FIGS. Iand II also. The spacer retainer is generally rectangular in shape andmay be made of a steel wire form, a length of steel channel, a steel baror any other type of high temperature melting point material. The airbar must be generally of a rectangular shape, or at least have twocritical dimensions. The one dimension is that the overall length of thespacer retainer must be such that it will frictionally fit into thespace between two adjacent side walls. See FIG. I for the positioning ofthe spacer retainer in position and the fact that its length is equal tothe spacing between two side rails 4. In addition, the width of thespacer retainer must be somewhat less than its length and must be suchthat it can pass into the opening 8 of the air weir. The spacer retaineris positioned with its long dimension extending along the slot 8 of theair bar. It is inserted within the air bar and then rotated 90 so thatthe length of the air bar then extends from one side rail to an adjacentside rail. The spacer retainer is now in position to provide support tothe side rail structure of the air bar so that these two side railscannot readily move towards each other.

In FIG. II, the spacer bar is shown being positioned by the center weirsupport 16 and also in the region between the center weir support 16 andthe end weir support 24. Naturally, there would be a spacer retainerbetween the center support 16 and the other end weir support of the airbar, which is not shown on the left side of FIG. II. The spacer retainer26 is retained in position due to its frictional contact with the siderails 4 and the fact than it rests upon the flanges 10 which define theair opening 8 of the air bar.

The spacer retainers herein will now provide for proper spacing of theside rails 4 of the air bar during a conventional two hour fire test.Should the high temperature melting point bars 18 and 22 be fluxed bythe melting weir support 16, spacer retainers 26 will still support theside rails 4 in position. In addition, the side rails will be supportedmidway between the weir supports so that there will be no buckling ofthe side rails in those positions. The spacer retainer is not restrictedto just the air bar shown in the drawings herein, but to any air barstructure which has an unusually long length and which is unsupported inits mid-regions. Such an air bar structure will tend to buckle during aconventional fire-rating test.

What is claimed is:

1. In combination, an air bar structure which has two side rails spacedthereapart to define an air passage, heat-meltable support means withinthe air bar and spaced along the length of the air bar to support saidside rails, said side rails having flange means extending outwardly fromthe air bar to support ceiling tiles of a suspended ceiling system, andspacer retainers within the air bar and positioned between the siderails to support and space said side rails, said spacer retainers beingmade of a high temperature melting point material and said spacerretainers being positioned in the air bar structure closely adjacentsaid flange structures to support said side rail structures so that theywill not collapse inwardly when the air bar structure is exposed to heatfrom a fire and the heat-meltable support means being melted partly bythe heat from a flre and no longer supporting the side rails.

2. The combination of claim 1 wherein the spacer retainers are notpositioned within the normalsupport structure for the air bars and saidspacer retainers are positioned at least in regions where there are nosupports between the side rails of the air bar.

3. In combination, an air bar structure which has two side rails spacedthereapart to define an air passage, aluminum support means within theair bar and spaced along the length of the air bar to support said siderails, said side rails having flange means extending outwardly from theair bar to support ceiling tiles of a suspended ceiling system, andsteel spacer retainers within the air bar and positioned between theside walls to support and space said side rails, said spacer retainersbeing made of a high temperature melting point steel and said spacerretainers being positioned in the air bar structure closely adjacentsaid flange structures to support said side rails so that they will notcollapse inwardly when the air barstructure is exposed to heat from afire and the aluminum support means has been melted has a width capableof being passed within the air outlet of the air bar structure and alength which is equal to the spacing between the side rails of the airbar so that the spacer retainer may be passed within the opening of theair bar structure and then rotated to be frictionally held within theair bar structure by the side rails of the air bar structure.

I UNITED STATES PATENT OFFICE CERTIFIQATE F QRREUHON Patent No.3,783,771 Dated January 8, 197

Inventor(s) Lyndon G6 Hartzell and James C. Ollinger It is certifiedthat error appears in the aboveidentified patent and that said LettersPatent are hereby corrected as shown below:

In the specification, column 2, line 19, "which" should be --which--, Inthe specification, column 2, line 61, insert the sentence "Fig. I hereinis ver similar-to Fig, 12 of the above-mentioned patent" before"Herein," In the specification, column 2, line 13, "than" should bethat. I

In the claims, insert dependent claim 3 into the application. The

reads as follows:

3, The combination of claim 1 wherein the spacer retainer is generallyrectangular in shape and such that it has a width capable of beingpassed within the air outlet of the air bar structure and a length whichis equal to the spacing between the side rails of the air bar so thatthe spacer retainer may be passed within the opening of the air barstructure and then rotated 90 degrees to be frictionally held within thebar structure by the side rails of the air bar structure.

in the claims of the patent,' claims 3, and 5 should be renumbered asclaims L, 5 and 6, Claim of the patent, now renumbered to claim 5,should be made dependent on claim Claim 5 of the patent, now renumberedto claim 6, should be made dependent on claim 1-.

Signed and sealed this 27th day of August 1974.

(SEAL) Attest:

MCCOY M, GIBSON, JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents 3 Foam POM-$50 (10-69) A USCOMM-DC 60376-P69 u.s4 GOVERNMENTPRINTING OFFICE: 1959 o-ass-ssa

1. In combination, an air bar structure which has two side rails spacedthereapart to define an air passage, heat-meltable support means withinthe air bar and spaced along the length of the air bar to support saidside rails, said side rails having flange means extending outwardly fromthe air bar to support ceiling tiles of a suspended ceiling system, andspacer retainers within the air bar and positioned between the siderails to support and space said side rails, said spacer retainers beingmade of a high temperature melting point material and said spacerretainers being positioned in the air bar structure closely adjacentsaid flange structures to support said side rail structures so that theywill not collapse inwardly when the air bar structure is exposed to heatfrom a fire and the heat-meltable support means being melted partly bythe heat from a fire and no longer supporting the side rails.
 2. Thecombination of claim 1 wherein the spacer retainers are not positionedwithin the normal support structure for the air bars and said spacerretainers are positioned at least in regions where there are no supportsbetween the side rails of the air bar.
 3. In combination, an air barstructure which has two side rails spaced thereapart to define an airpassage, aluminum support means within the air bar and spaced along thelength of the air bar to support said side rails, said side rails havingflange means extending outwardly from the air bar to support ceilingtiles of a suspended ceiling system, and steel spacer retainers withinthe air bar and positioned between the side walls to support and spacesaid side rails, said spacer retainers being made of a high temperaturemelting point steel and said spacer retainers being positioned in theair bar structure closely adjacent said flange structures to supportsaid side rails so that they will not collapse inwardly when the air barstructure is exposed to heat from a fire and the aluminum support meanshas been melted partly by the heat from the fire and no longer supportsthe side rails.
 4. The combination of claim 1 wherein the spacerretainers are not positioned within the normal support structure for theair bars and said spacer retainers are positioned at least in regionswhere there are no supports between the side rails of the air bar. 5.The combination of claim 3 wherein the spacer retainer is generallyrectangular in shape and such that it has a width capable of beingpassed within the air outlet of the air bar structure and a length whichis equal to the spacing between the side rails of the air bar so thatthe spacer retainer may be passed within the opening of the air barstructure and then rotated 90* to be frictionally held within the airbar structure by the side rails of the air bar structure.